


be me for a while

by cassandralied



Category: It's Always Sunny in Philadelphia
Genre: Alternate Universe - Vampire, Blood Drinking, Implied/Referenced Child Abuse, Implied/Referenced Rape/Non-con, Let the Right One In AU, M/M, Violence, basically just the ot3, can be read as platonic, canon typical trauma
Language: English
Status: In-Progress
Published: 2020-09-14
Updated: 2020-09-16
Packaged: 2021-03-07 04:55:20
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 2,730
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26467543
Author URL: https://archiveofourown.org/users/cassandralied/pseuds/cassandralied
Summary: “Are you lost, dude?” he asked.The kid shook his head. Hesitated, then nodded.“Do you want to come home with me?” Another careful nod.“Cool. I’m Mac. You can be my best friend. What’s your name?”That’s how it started.--Let the Right One In AU
Relationships: Charlie Kelly/Dennis Reynolds, Charlie Kelly/Mac McDonald, Charlie Kelly/Mac McDonald/Dennis Reynolds, Mac McDonald/Dennis Reynolds
Comments: 6
Kudos: 28





	1. may i come in?

“Is that true?” Charlie asks on their walk home, with the blood still rushing in Mac’s ears. He looks down at the scruffy kid that he’s adopted — if not the other way around. “What?”

“What they said.” Charlie glances up. His eyes are green when he’s like this. “That I’m your boyfriend or whatever.”  
Mac laughs, a rush of empty air. But he’s still thinking about what Charlie had done to that alley cat, still filled with relief that the bullies hadn’t turned out the same way, eyes gouged, faces missing, shit that was way cooler on TV than in real life.   
“No, dude. That’s gay. They were just being shitheads. We’re best friends, bro! That’s even better.”  
“Okay,” says Charlie amiably. “Besides, I’m not really a boy.”

Mac looks down at him. “Yeah? What are you?”  
“A vampire, Mac.” Charlie says it like _duh_ , and Mac laughs. He can’t help it. “Guess you’re right.”

********************************

  
When Charlie starts getting freaky and pale again, and trying to chew on Mac’s neck in his sleep, Mac goes to Dennis for help. Despite being their age, Dennis knows all kinds of smart shit. He’ll know how to fix this.  
He’s smoking by the gym in a blue polo shirt, trying to look like he’s not avoiding anyone.  
“Hey, Mac.” Dennis flicks his cigarette.  
Mac feels his face smile without him consciously meaning to, like a _Palvolian_ reaction or whatever. “Hi, Dennis!”  
“Who’s the kid?”

Charlie studies Dennis with that same blank expression he had before he ate the cat, so Mac hastily intervenes. “Charlie, this is Dennis. He’s a friend. Den, this is Charlie.”  
“A pleasure,” Dennis says dryly, which is one of his weird adult things. He says it like he’s annoyed Mac brought someone else to their hangout spot. Then to Mac, “Does he talk?”  
Charlie lets out something that might very possibly be a growl.  
Mac sighs. “We need help, Dennis.”  
“Yeah?” and that’s the Dennis everyone else knows, cold and aloof and not-giving-a-shit. “Better make it worth my time.”  
“Show him your teeth, Charlie."

Charlie obliges.

********************************

“You need blood.”

“Yeah, dude, a lot of it.”

They’re throwing rocks —well, Charlie and Mac are. Dennis is pretending he’s too cool but Mac thinks he might want to join in a little.  
“So you need people who won’t be missed.” Dennis considers. “What about hobos?”  
“Taste bad,” Charlie says, the first words he’s spoken in Dennis’s presence.

Dennis just shrugs. “Yeah, that makes sense. Not very hygienic, either. What if we just find, like, a huge loser that nobody will miss?”  
“Like your sister?” Mac asks — Dennis glares, and he shuts up.  
“I don’t wanna eat a sister,” Charlie sounds petulant. Dennis sighs.

“So, we need to find someone who doesn’t do drugs and won’t be missed.” His eyes light up. “I’ve got it.”

  
That night, Mac and Dennis take Charlie to a nice little suburban place across town. They open the door easily —Dennis knows where the spare key is, because Dennis knows pretty much everything.   
“Promise you won’t look inside,” Charlie says, his voice small and oddly solemn. “No matter what you hear.”  
They both promise. Mac makes a Boy Scout swear even though he never was a real Boy Scout. Charlie hesitates, and Dennis claps him on the shoulder. “Go on, buddy. Have fun.”

They hold the door to the school librarian’s house shut after Charlie slips in.   
Just in case she tries to run.

********************************

“Where the hell did you find him?” Dennis asks. Charlie’s curled up in a pile of blankets on the floor, still covered in blood and various bits of gore. Mac checks to make sure their friend is asleep before starting his story.

He’d found Charlie on Christmas, by the train yard and covered in dried blood, his face entirely smeared with it.  
“Jesus fuck!” Mac had shouted. On purpose, as a scaring tactic. Not because he was surprised or freaked out or anything.  
Charlie had blinked up at him, all big eyes, and blood or no, Mac couldn’t just leave him like that.  
“Are you lost, dude?” he asked.  
The kid shook his head. Hesitated, then nodded.“Do you want to come home with me?” Another careful nod.  
“Cool. I’m Mac. You can be my best friend. What’s your name?”

That’s how it started.

  
********************************

The first time Charlie talks about his past, it’s around one in the morning and he and Mac are curled up on the basement couch. Mac keeps thinking his parents are going to notice the second scruffy kid running around, or the fact that Mac is rarely sleeping in his bed anymore.  
They don’t.

Charlie’s head is on Mac’s shoulder, his breathing deep and even. Mac isn’t sure if he really needs to breathe, or if he’s doing it to make Mac feel better, and he doesn’t really want to break the silence by asking.  
“There was a girl on the train,” Charlie whispers suddenly, his voice both muffled and louder in the dark.Mac doesn’t say anything.  
“Her mother worked for the train company, I think. She found me the first day. Didn’t turn me in. Snuck me food instead. I couldn’t, like, actually eat it, but it was nice of her.”  
He pauses, and Mac knows, horribly, what’s coming. Still he asks. “Did you kill her?”  
Charlie’s eyes fill with red tears. “I don’t remember.”  
They spend the rest of the night in silence, watching the sun come up.

  
********************************

“I need to borrow Charlie.” Dennis looks calm, but Mac knows better. He wonders if his heartbeat changes when Dennis is around — Charlie would probably know.  
“Why?” Mac, almost unconsciously, moves in front of his smallest friend. He doesn’t think Dennis would hurt Charlie even if he were capable of it without getting ripped into a million billion pieces. But Mac doesn’t like that scheming look in Dennis’s eye, either.  
“It’s okay, Mac,” Charlie says, ducking under Mac’s arm. He gets sluggish when he hasn’t eaten in a while, and he’s like that now: pale, wan, eyelashes fluttering. He smiles at Dennis, then at Mac, with effort. “We’ll see you later.”  
As Charlie takes Dennis’s hand, Mac hears him ask, “Can we go to the Toys R Us?”  
“Sure, buddy. Whatever you want.”

Charlie comes back suspiciously clean, smelling of expensive soap and wearing a brand new t-shirt instead of the yellow one of Mac’s. He excitedly shows Mac the giant teddy bear Dennis bought him, and the little robot. Dennis comes back with one of those large swirled candy lollipops, the ones Mac and Charlie look at in the window but can’t afford.  
He lets Mac share it with him while they watch some old black and white movie that they’re pretty sure Dennis picked only because it has a vampire.

The next day it comes over the news that Tim Murphy’s gone missing.


	2. but you'd like to, [...], to get revenge. right?

**Summary for the Chapter:**

> more feral vampire (& friends!) shenanigans (this time with more dennis pov!)

“Dennis?” They go to the candy store first. Candy store, then Tim’s house, then an unmarked grave, home for a shower, then Toys R Us. Dennis has it all planned out.   
He pays —or, technically, Dee’s allowance pays — for a bag of sour candies, and one of those big lollipops Mac’s always staring at.

“What’s up?” In the mirror behind the register, only Dennis’s reflection shows consistently. Charlie’s sort of flickers in and out.  
“I lied to Mac,” the kid says, all guilty.  
Dennis laughs. “Is that what’s bothering you? Buddy, we all lie to Mac. It’s practically what he’s there for.”  
Charlie doesn’t look convinced.

"Come on, what did you tell him?”  
“That I don’t remember killing my family.” Charlie’s voice is very small. He’s still holding Dennis’s hand. “That I didn’t do it on purpose.”

Holy fuck.  
Dennis gives him a sour candy to sniff. The kid looks like he needs it.

  
********************************

  
“Are you gonna tell Mac what I said?” Charlie asks on the way back from Toys R Us. Somehow, he’s already gotten the teddy bear dirty, despite the fact that it cost a hundred bucks and they literally just left the store. With effort, Dennis doesn’t yell at him for it.

“I assume you don’t want me to tell him.”  
“Yeah.”

“Then I won’t.” He probably even means it. Charlie smiles, bright and bloody.

“Oh, shit, dude, you have so much gunk in your teeth. We need to stop and buy you a toothbrush before we drop you at Mac’s place.”  
Charlie picks idly at the pinky-red thing — it looks like a shredded muscle — stuck in his canines, and spits it out on the ground. “Yeah, good catch.”  
He pauses. “Mac isn’t gonna know that we ate somebody?”

“ _You_ ate somebody. No, he’s going to find out. We’re just not going to be the ones to tell him.”  
Dennis knows Mac. If he told him outright, he might feel like he could confront him about it with some of his _murder is wrong bullshit_ , as if murder doesn’t happen all the time in that stupid Bible. As if Mac hadn’t brought Charlie to him in the first place for this exact purpose.

“Okay,” Charlie says dubiously. “Hey, can I get the robot in the window too?”  
“Charlie, we just left.”  
Charlie sticks his lower lip out, and Dennis thinks about the fact that if it wasn’t for this probably illiterate, weirdly adorable little dumbass and his giant razor teeth, his life would be a whole lot shittier.  
“Fine.” He passes over the remains of Dee’s piggy bank. “Go get the fucking robot. Just hurry.”  
Charlie beams.

********************************

Dee’s been snooping around in his stuff more than usual, coming out of his room looking more frustrated every time. Finally, she snaps and just comes up to him, her stupid back cage rattling. “Are you killing people?”  
“No.” Technically, it’s Charlie doing the killing. Dennis is just providing a little help.   
Dee actually _stomps her foot_ , like some kind of baby. “I’m going to find out what you’re up to. You might as well save the time and tell me now.”  
“Good luck with that,” Dennis says, and Dee storms off, probably to go write something sad in her diary.

********************************

  
“Mac’s scared of you.”  
Dennis scoffs. “No, he’s not.”  
“His heartbeat picks up when you’re around. What else does that mean?”  
“Oh,” Dennis says, and then, _“Oh.”_  
“Like yours just did,” Charlie says, unhelpful as always.  
Dennis gives him a dirty look, half-hearted as it is. “Change the subject.”

  
********************************

  
Mac may have picked the wrong time to make a joke, he’ll admit that now. With his head being held underwater while he thrashes and flails uselessly against an iron grip, yeah, maybe he might have done some things differently.  
Mac can’t hold his breath three minutes. He’s pretty sure nobody in the world can do that. Why the fuck would he say that? Already, little dancing spots are beginning to fill his vision.

There’s a distant sounding crash, and something splatters into the water, hot. Jesus, are they pissing on him now? He’ll kick their asses when he gets out of this, he really will. 

As if by the power of that thought, the grip on him slackens suddenly and Mac pushes his way to the surface, gasping.  
The pool is red.  
Not entirely red like the Red Sea in the Bible, but there are definite dark splotches in pale water, like picked and bleeding scabs on delicate blue skin. 

Charlie is halfway across the room, picking up a screaming kid and sinking his teeth into their neck. Mac can’t stop staring. Blood gushes like a fountain, like in the movies, splattering Charlie’s face and hair and neck. 

Dennis is there suddenly, yanking Mac out of the water (well, okay, Mac does most of the work getting out but it’s the thought that counts) and wrapping a towel around his shoulders. “You okay, man?”  
The hand that had held him under, with the rest of the forearm, is floating sickly on the pool’s surface, trailing dark fluid. Its former owner is nowhere to be seen. Mac coughs out water and shock, Dennis hitting him between his shoulder blades.

Charlie trots over —he’s left no one alive. “Hey,” he says casually. There’s more blood on him than a single person could ever generate. “Guys?” There are scratches on his face, like somebody was desperately trying to claw their way free.  
“Hey, Charlie,” Dennis says weakly when it doesn’t seem like Mac is going to respond.

“Can we get pizza?” Charlie asks. “I like the grease smell in the store.”

********************************

Dennis pays for the pizza, and he’s the only one who’s actually eating it. Charlie’s practically curled into Mac’s side (nobody in the store has commented yet on the blood that he’s absolutely drenched in). Mac is still in shock, clearly, given that he hasn’t registered anything Dennis or Charlie has been saying.

Dennis isn’t really sure what to do with that — with these two crazy kids who might as well be his only friends — so he invites them to stay the night.  
Charlie asks, “Can I sleep in bed with you? I don’t like being alone. That’s when the Nightman comes.”  
“Uh, sure.” He glances at Mac for confirmation on this mysterious figure who scares _Charlie_ , but Mac’s staring blankly at the wall.

********************************

  
“Is Mac mad at me?”  
Dennis stares. “How the fuck would I know?”  
Charlie shrugs. They’re whispering, all squeezed together in Dennis’s bed. (He’d made Charlie shower three times before letting him in the room.) Mac is snoring softly.

“He’s not talking to me,” Charlie says, as if this is a conversation Dennis wants to continue.  
Dennis huffs out a sigh. “You killed a lot of people, Charlie. In really fucking nasty ways. He’s still, like, adjusting.”  
“But they were hurting him,” Charlie protests, and Dennis shushes him. He continues, quieter. “It wasn’t bad if they were hurting him already, right, Dennis?”  
“Try to get some sleep,” Dennis says instead of answering, because what is he supposed to say to that when he hasn't even figured it out himself. Charlie hugs him tightly and rests his head over Dennis’s heart. “It’s going to be okay," the kid reassures.

It isn’t okay.

********************************

Dennis was careless, he knows that now. He left Charlie sleeping upstairs to take Mac out for breakfast, try to figure out whether his best friend was now a vegetable thanks to trauma or whatever. Mac had woken up pretty normal, and even the quiet shock lingering in his eyes didn’t dull the conversation that much.

Dee must have did something wrong, the dumb bird, because they’re halfway back when they hear her screams from the house. Slamming their way up the stairs with their shoes still on, they’re fully prepared to see Dennis’s sister horribly mangled and looking even grosser than usual.

She’s not, which is kind of a nice surprise. She’s crumpled against the floor, hyperventilating, but nothing’s broken or bleeding. The wall’s dented from where Charlie threw her against it. If it wasn’t for her back brace, Dennis will muse later, he could have snapped her spine.  
Or her neck.

Charlie’s growling, low in his throat. He’s never looked more like a wild animal.  
“Charlie!” Mac shouts. “Dude, what happened?”  
“Attacked me,” the hunched figure on the bed replies, and Dennis and Mac exchange looks. It’s definitely a bad sign when Charlie isn’t using all the words he possibly can.

Dee squawks in protest. “I attacked you? I poked you in the ribs, dipshit!”  
“Charlie. Charlie.” He needs to find a better way to calm his friend down. Dennis takes a hesitant step forward, hands outstretched. Out of the corner of his eye, he sees Mac stepping closer too, as if to grab Charlie if he lunges.

“This is just Dee. She’s my sister. She’s kind of a bitch, but she’s not going to hurt you, Charlie. I promise. She’s gonna apologize.”  
Charlie looks unconvinced.“What?” Dee snaps. But she does, sullenly, straightening up from where she’d been crumpled on the floor.  
“Sorry, uh, Charlie. I thought you were dead or something. You weren’t breathing. I didn’t wanna scare you.”  
Charlie’s eyes flick to Dennis, then Mac, and then to the floor. “S’okay. I thought you were…” he mumbles. “Someone else.”  
“Who?” Dee asks, nosy bitch that she is.

Charlie looks up. “Do you wanna go throw rocks at trains?”  
Weirdly, that makes Dee smile. “Sure.”

**Author's Note:**

> idk what to be more embarrassed about,, that my first fic for this fandom is a Let the Right One In au or that i say 'my first fic' as if there are more to come.


End file.
